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POASP.Net - Update controls inside an Update Panel when raising an event
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  1. POASP.Net - Update controls inside an Update Panel when raising an event
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    copied!<p>ASP.Net noob here trying to update a control inside an UpdatePanel inside a method subscribing to an event, with no luck.</p> <p>Some background, I have written a DLL that interfaces with a standard POTS telephone and I have mapped various occurences on the phone end (phone being picked up, phone ringing etc) to .Net events.</p> <p>In my ASP.Net solution, I have added my DLL, instantiated my phone and, in methods subscribing to my events I want to update various labels inside an UpdatePanel with information inside the EventArgs objects being passed into my methods.</p> <p>Using breakpoints, I can see that my Phone object is functioning as expected, the events are being raised when they are supposed to and the EventArgs contain the information they are supposed to.</p> <p>But the labels inside the UpdatePanel never update. I wrote the previous version of the application as a Windows Form, and I recall that whenever updating the UI from another thread, I had to check whether <code>InvokeRequired</code> was true first, and if so call the <code>Invoke</code> method but I don't know what the equivalent to this is in ASP.Net (if there is one).</p> <p>Markup is below (this is just an example project I have created to get my head around the basics):</p> <pre><code>&lt;%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplication2.WebForm1" %&gt; &lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt; &lt;html xmlns="http://www.w3.org/1999/xhtml"&gt; &lt;head runat="server"&gt; &lt;title&gt;&lt;/title&gt; &lt;style type="text/css"&gt; #form1 { text-align: center; } &lt;/style&gt; &lt;/head&gt; &lt;body&gt; &lt;form id="form1" runat="server"&gt; &lt;asp:ScriptManager ID="ScriptManager1" runat="server"&gt; &lt;/asp:ScriptManager&gt; &lt;asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional"&gt; &lt;ContentTemplate&gt; &lt;asp:Label ID="Label1" runat="server" style="text-align: center" Text="Label"&gt;&lt;/asp:Label&gt; &lt;br /&gt; &lt;br /&gt; &lt;asp:Button ID="Button1" runat="server" Text="Button" /&gt; &lt;/ContentTemplate&gt; &lt;Triggers&gt; &lt;asp:AsyncPostBackTrigger ControlID="ScriptManager1" EventName="Load" /&gt; &lt;/Triggers&gt; &lt;/asp:UpdatePanel&gt; &lt;/form&gt; &lt;/body&gt; &lt;/html&gt; </code></pre> <p>Now for the code:</p> <pre><code>using System; //My DLL using Maximiser; namespace WebApplication2 { public partial class WebForm1 : System.Web.UI.Page { //My Phone Object private Phone _ThisPhone { get; set; } protected void Page_Load(object sender, EventArgs e) { //Instantiating Phone Object with IP Address and Port _ThisPhone = new Phone("8.8.8.8", 8888); //Hookstate event indicates phone is off/on the hook _ThisPhone.HookState += new EventHandler&lt;Maximiser.Events.Hookstate&gt;(thisPhone_HookState); } void thisPhone_HookState(object sender, Maximiser.Events.Hookstate e) { //I want to update my Label with the phones current HookState Label1.Text = e.State; //Now I want to refresh the UpdatePanel but not reload the page UpdatePanel1.Update(); } } } </code></pre> <p>The method is definitely running as shown below:</p> <p><img src="https://i.stack.imgur.com/5eUt7.jpg" alt="Breakpoint"></p>
 

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